price



v 2 Shets-Sheet 1.. W. G. KENT 82; H. S. PRICE.

(No Model.)

PISTON.

Patented Dec. 30, 1890.

(No Model.) W. G. KENT 8v H. S. PRICE.

PISTON.

No.-443,857. Patented Dec. 30, 1890-.

L a L fiimes W 7-2 Sheets-Sheet 2. v

4 I UNITED STAT S PATENT OFEIcE.

\VALTER G. KENT AND HENRY SAMUEL PRICE, OF LONDON, ENGLAND.

PISTON.

SPECIFICATION forming part of Letters Patent No. 443,857, dated December 30, 1890.

Application filed April 14, 1890- Serial No. 347,810. (No model.) Patented in England February 16 1889, No. 2,772.

To all whom it may concern: 7

Be it known that we, WALTER GEORGE KENT, manufacturer, residing at 199 High Ilolborn, \V. 0., in the county of Middlesex, England, and HENRY SAMUEL PRICE, engineer, residing at 46 Bonnington Square, in the county of Surrey, England, subjects -of the Queen of Great Britain, have invented certain new and useful Improvements in Pistons, (for which we have received Letters Patent of Great Britain, No. 2,772, dated February 16, 1889 5) and we do hereby declare the following to be a full, clear, and exact de scription of the invention, reference being had to the accompanying drawings, which form part of this specification.

Our invention relates to an improved construction of piston more especially intended for use in liquid meters, motors, or pumps, but also suitable for other forms of apparatus in which pistons are employed.

In the accompanying two sheets of drawings, Figure 1 is a sectional elevation, and Fig. 2 a plan, of a piston constructed according to our invention. Figs. 3 and at are sectional elevations of pistons, showing slight modifications in the arrangement of some of the parts.

Similar letters of reference denote similar parts throughout the drawings.

Referring to Figs. 1 and 2, which represent a piston as constructed more particularly for use in a water-meter, A is a circular disk or plate fitting loosely the bore of the cylinder B. On each side of the said disk a washer 0, formed of leather, rubber, or other suitable elastic material, is placed. These washers O C are so shaped or molded with an annular corrugation or hollow 0 around the outer part that while the central part of the washer lies flat upon the disk A and the extreme edge is also in contact with the disk the intervening part is curved away from and out of contact with the disk. A metal plate or washer D, of the same form in cross-section as the elastic washers C C, is fitted over each such elastic washer, and the whole held together by a nut E on the end of the piston-rod F against a shoulder on the rod. Any other suitable arrangement may, however, be employed for securing the parts of the piston on the rod.

Holes H are formed in the curved part of each outer metal disk D.

fluid, having access to the outer surface of the washer C by means of the holes H in the plate D, will slightly compressor flatten the curved part 0', thus forcing the edge of the washer outward into close contact with the cylinderwall, it being unable to escape downward, be 'ing supported by the disk A, and so making a tight joint. \Vhen the piston begins to move under the influence of the pressure, there might under certain conditions be a tendency for the edge of the washer C to stick to the cylinder-wall,which, if permitted, would allow the disk A to move away from it, and a distort-ion of the form of the washer would result. The edge of the plate D, however, confines the edge of the washer against the disk A, thus compelling the whole to move together, and the curved part of the plate insures the washer retaining its form. hen the pressure is out 01f at the end or other desired part of the stroke, the washer C resumes its original shape, and the pressure being admitted at the end of the stroke to the under side of the piston the same effect will take place on the lower washer.

If the piston be supposed to be that of a pump and moving in the same direction as before, the fluid pressure will be on the under side, being caused by external force applied to the piston-rod, and in this case it will be the under washer which is performing the work. There would be no tendency for the under washer to separate from the disk A; but the upper washer, although not pressed outward by the fluid, might have sufficient friction against the cylinder to cause it to leave the disk if not secured by the upper plate D. It will thus be seen that these plates D, in combination with the disk A, perform an important part in the action of the piston.

In the piston shown in Fig. 3 the central disk A is much thicker. This form of piston is applicable for force-pumps or steam-engines where the increased pressure would bend or distort the thin disk shown in Fig. 1.

In cases where only one side of the piston is subjected to pressure, as in a single-acting pump, an elastic washer on that side of the piston only is required. Such an arrange ment is shown in Fig. 4.

Although we have only represented in the drawings pistons formed with a single annular corrugation or hollow C, two or more concentric corrugations maybe employed, if desired, the external washers D being shaped to correspond therewith, and when the pistons are used for very heavy pressure we may place rings or cushions, of rubber or other suitable elastic material, under the curved parts 0 of the washers to assist their restoration to form when the pressure is removed.

Rings of various patterns may be employed. Thus in Fig. 3 a ring J, having a curved upper surface with ribs on the under side, is shown applied to the top washer l, while a solid. ring K is shown for the bottom washer. In. Fig. 4 a tubular ring L is shown.

Our improved piston is specially suitable for use in place of the ordinary hydraulic cupleather packing, as it will form an equally tight joint with a far less amount of friction and consequent loss of power than is experienced in cup-leathers,especiallywhen working under high pressure, and owing to the small amount of surface in contact with the cylinder-walls the liability of the. piston to stick is greatly reduced. The elastic washers will remain tight and automatically compensate for wear until they are so far worn that the entire washer lies flat and in contact with the disk A.

Having now described our invention, what we claim, and desire to secure by Letters Patent in the United States, is-- 1. A piston wherein the packing consists of one or more corrugated elastic washers C, in combination with a disk A and external plates D, the said washers being extended by the pressure of the fluid in the. cylinder, and thus forming a tight joint against the cylinderwalls, substantially as herein set forth.

2. The combination, with the disk A, extern al plate I), and corrugated elastic was-her C, of an elastic ring located between the plate A and washer C, substantially as described.

\VALTER G. KENT. HENRY SAMUEL PRICE.

\Vitnesses:

'AMBRosE MYALL, 21. Cockspzm' St, London, S. TV.

'1. F. BARNES, 28 Southampton Bdga, London, TV. (I'. 

